There's no way to eliminate weather threats. But it is possible to get better at predicting them.

For the last four decades, scientists have depended on the National Center for Atmospheric Research, or NCAR, and its sophisticated computer models to forecast everything from the intensity of a thunderstorm to the track of a hurricane.

With the recent unveiling of Yellowstone — the world's fastest supercomputer devoted to climate research — housed at the NCAR-Wyoming Supercomputing Center (also called the NWSC) in Cheyenne, Wyoming, those weather projections just got a lot more accurate.

What is a supercomputer?

A supercomputer is a very powerful computer that can perform calculations at incredible speed.

The world's fastest supercomputer can hit a speed of 20 petaflops, which means it can run 20,000 trillion calculations per second. (That's equal to 7 billion people solving 3 million math equations every second).

Depending on its purpose, a supercomputer can be used to solve practical business problems, like figuring out how to package potato chips, to answering larger science questions, like simulating what happens when a nuclear bomb explodes or understand how climate is changing.

The main purpose of the Yellowstone supercomputer is to run numerical simulations of physical systems, like the atmosphere and the ocean.

For a simulation, you begin with a set of initial conditions — typically from land and weather observations made over the last half century that stream in from organizations like NASA and the National Oceanic and Atmospheric Administration. All of that data, which is essentially a snapshot of the planet, is stored in the massive computer's data centers.

The model then moves that snapshot forward in time using mathematical equations describing how things like air and moisture move around in Earth's system, provided by the researchers. The computer breaks the problem up into little pieces and runs them across thousands of processors. In that process, the computer determines how those equations will change the initial conditions over time.

Some models will integrate for a century into the future or even longer. Others may integrate over two weeks — essentially a very detailed weather forecast.

"In some ways, it's the mathematical equivalent of a telescope," Rich Loft, the researcher who directs technology development within NCAR's computer lab, told Business Insider. He played a key role in bringing Yellowstone to life.

"A telescope lets you see farther than you can see with your own eyes," Loft said. Similar to that, he said: "the computer allows you see the consequences of the mathematics well beyond what you can ever hope to do with pencil and paper."

Yellowstone's computing muscle

Yellowstone is a 1.5 petaflop supercomputer, which means it can run 1,500 trillion calculations per second. This puts Yellowstone among the top 25 speediest supercomputers in the world and makes it about 30 times more powerful than its predecessor supercomputer, Bluefire.

Thirty times more computing means researchers can do a lot of things that were simply impractical before, like examining how ocean currents affect rain distribution or seeing areas of rotation that could create a tornado within a larger thunderstorm.

"It's like getting roughly 10 times more megapixels in your camera. With better resolution, you get crisper images of what's going on in the Earth's systems," Loft said.

For people who model the center, or eye, of hurricanes, that means being able to construct a much more realistic and less smeared out picture of the eye wall and its wind gusts — which is typically what causes the most damage to structures.

"Think about a very low-resolution picture and then a much higher resolution picture of the same thing — you get a much better feel for what you're looking at, " says Loft.

"[Yellowstone] will provide an excellent testbed for improving hurricane prediction," said Loft. This includes the ability to predict the track and intensity of a hurricane with greater accuracy.

"You need higher resolution to get the intensity right, and you need a lot of statistical information to get a good picture of where [the hurricane] is going to strike," explains Loft. The more models the computer can run, the clearer the picture of the hurricane's future becomes.

A better understanding of climate change

Although Yellowstone is designed to study a range of Earth science topics, including space weather, air quality, water aquifers and energy production, about half of Yellowstone's work load focuses on climate modeling.

"The thing about climate is that we have a very good consensus between observation and theory in computer models, which all show that there is going to be climate change."

Most climate models show that the temperature is going to rise depending on how much carbon dioxide is released into the atmosphere. (Since temperature records began in 1880, nine of the 10 warmest years have occurred since the year 2000 and the first half of 2012 was the hottest in U.S. history). This long-trend mapping is good, but it doesn't tell scientists how that temperature change affects the redistribution of energy within the system, explains Loft.

And that's important because it impacts things like rainfall (and the lack of rainfall that causes drought) around the world. Some places under climate change are likely to lose rainfall, which will affect crops and water supply. Some people are going to get more rain, milder temperatures and a longer growing season.

A more powerful computer can answer these questions. Yellowstone not only allows researchers to predict whether it's going to be warmer in a century, they can also look 10 or 20 years into the future and make a probabilistic prediction as to what the weather will look like in a given region.

"When you talk to government officials, city planners, state water boards, or insurance companies, they want to know specific information on a regional level. You can't answer those questions with a coarse-grain model," said Loft. "Yellowstone is going to give us answers to some very important unfinished business in atmospheric science."

Creating a supercomputer that can perform at such a high level requires a lot of work. See how it came together.